Photochemical transformation of pyrene and benzo[a]pyrene vapor-deposited on eight coal stack ashes

The photochemical decomposition of pyrene and benzo-a-pyrene, as adsorbates deposited from the vapor phase, was examined on eight coal stack ashes. Similar studies using alumina, silica gel, and controlled-porosity glass and graphite adsorbents were also performed. Phototransformation of the adsorbates proceeded more slowly on any of the ash substrates than on alumina, silica, or glass surfaces. Those ashes relatively high in carbon and/or iron content were especially effective at suppressing photodegradation of adsorbed pyrene or benzo-a-pyrene.